Tanning hides and skins



Patented Oct. 20, 1931 UNITED STATES PATENTOFFICE JEFFREY DENNISS AND THOMAS REID, OF SYDNEY, NEW SOUTH WALES, AUSTRALIA TANNING HIDES AND SKINS No Drawing. Application filed November 29, 1929, Serial No. 410,634, and in Australia January 21, 1929.

This invention concerns a process for tanning animal hides and skins, in which the cost of production is low and the time required for manufacture is considerably less than in existing methods, while a leather of excellent wearing qualities without the objectionable odour wiich so frequently accompanies tanned goods is produced. 7

After the usual preliminary softening and plumping treatment, the hides or skins in wet condition are placed in vacuo, or in partial vacuowhich should not be less than 14 lbs. sub-atmospherefor about six to twelve hours, and then lime liquor is introduced into the vacuum chamber. hey remain submerged in the lime liquor until fit for de-hair ing, about five or six days and they are then washed to remove lime. Next follows the usual beam-house treatment, at the conclusion of which they are immersed in liquor of strength about 12 barkometer for a period of one to two days. Thereafter the hides or skins are hung or packed in layers with ground tan bark and covered with tan vegetable liquor in specially constructed tan pits; these pits are enclosed and they are held in a state of vacuum as complete as practicable for a period of two days. After this vacuum treatment the pelts are immersed in pure concentrated tan vegetable liquor not less than barkometer in strength, and according to their substance are retained therein from ten to thirty-five days. The leather thus produced is subjected to the usual finishing operations and may be dyed to bring it to any colour desired.

The fibre becomes tightened up in the process even on the loosest belly pieces, and a firm tough leather having good wearing properties is obtained.

Loss in weight during the process, due to corrosion and solution of the hides or skins is low. The wearing qualities of the product are not diminished as in most known quick tanning processes.

What we claim as our invention and desire to secure by Letters Patent is A process of tanning hides and skins, comprising'the sequential steps of preliminarily softening and plumping the hides, maintain- 

